MINNEAPOLIS — Joba Chamberlain is scheduled to begin a throwing program Friday, the first step in his return to the New York Yankees rotation.

Chamberlain initially said he would start throwing on Wednesday, but manager Joe Girardi said the right-hander will begin on Friday when the Yankees return home to start a series against Kansas City.

"I made the suggestion he waits until Friday and does it in front of our people," Girardi said before the Yankees played at Minnesota on Monday night.

Chamberlain was placed on the 15-day disabled list last Wednesday due to rotator cuff tendinitis in his pitching shoulder.

The 22-year-old was removed from his start Aug. 4 against Texas in the fifth inning with stiffness in his shoulder. He expects to rejoin the Yankees' rotation before the end of the month.

Chamberlain is 4-3 with a 2.63 ERA in 32 games, including 12 starts.

"Play catch and just go from there," Chamberlain said Monday at the club's complex in Tampa, Fla.

Girardi called it a "very positive sign" that Chamberlain is getting ready to start throwing, but wouldn't put a timetable on his return to the mound.

"We'll have to see how long it takes," Girardi said.

New York's rotation has been ransacked by injuries all season, with Chien-Ming Wang, Phil Hughes and Carl Pavano, of course, out of the mix. When healthy, Ian Kennedy has been ineffective.

Sidney Ponson, who started Monday night's game against the Twins, has been a capable fill-in, but Girardi said before the game he still wasn't sure who would start the series finale on Wednesday.

Also, designated hitter-left fielder Hideki Matsui ran the bases for the first time since being sidelined in late June by a left knee injury. He could start playing in minor league rehab games soon.

"If everything goes well, I think in a couple days," Matsui said through a translator. "I feel like I've been making good progress every day. Taking a good step forward each time."

Matsui has appeared in 69 games this season, hitting .323 with seven homers and 34 RBIs.

Girardi said Matsui could begin a rehab assignment by the end of the week.